Unions, airlines and airport executives were all scratching their heads when it was revealed last year that a dozen or so U.S. Customs and Border Protection agents would be stationed in the Emirati capital - clearing passengers bound for the United States so that on arrival, they would zoom through the airport like domestic travelers.

Anyone who has ever waited for an hour or two or more to clear immigration at one of America's international airports can see the benefit of flying on an airline that effectively eliminates that. Why, it's better than taking your luggage with you on the plane to avoid baggage claim.

The question industry leaders like Airlines for America had was this; Why provide Etihad with this competitive advantage over U.S. airlines, none of which fly out of Abu Dhabi?

The idea of pre-clearing travelers to reduce immigration wait times at ports of entry is a good one. On a visit to New Zealand in 2011, quite a few Kiwis told me when traveling they choose any route other than one that takes them through the United States, which of course means any airline but an American one. Who can say how much money is lost because of this?

DHS Secretary Janet Napolitano argues that having American immigration officers on the ground at these foreign airports improves security - giving U.S. agents a level of control beyond our borders. Better to check the passengers before they get on the plane than after they are airborne, she told The New York Times.

Popular international destinations for Americans like Aruba, Bermuda, eight cities in Canada and two cities in Ireland already preclear travelers alleviating a bit of congestion. With 80 million people traveling to the U.S. each year it doesn't seem too hard to come up with a list of candidate airports where adding pre-clearance could do even more to reduce wait times at immigration halls while offering some benefits to U.S. airlines too.